Ratchet mechanisms typically involve wheels or bars having inclined teeth, in which a pawl drops so that motion can be imparted to the wheel or bar, governed, or prevented. Rachet mechanisms are usually employed in hand tools of different kinds, such as wrenches, screwdrivers, and the like, in order to allow effective motion in one direction and prevent motion in the opposite direction.
Examples of tools using rachet mechanisms are given by U.S. Pat. No. 4,441,387 (Hendricks), and U.S. Pat. No. 4,524,652 (Wenzel et al.), among many others.
A large number of greatly diversified applications utilize also ratchet mechanisms in cases where effective unidirectional motion is needed. These applications may include drastically different end-uses, such as for example sailing winches, dental floss disposers, seat belt retractors, security entry systems, spinning reels, control manifolds, reclining mechanisms, labelers, mop connectors, faucet valves, exercise devices, printing apparatuses, cable hoists, and kite reels, to mention a few.
One of the biggest disadvantages of conventional ratchet mechanisms is that for the pawl to move from one tooth and engage the next tooth, the handle has to turn by an angle of typically 15-20 degrees. In addition, since the teeth are inclined, the backward motion required to engage a tooth starting from the preceding tooth is larger than the effective forward motion to turn the ratchet wheel, and thus additional "dead" space is needed. If there is no adequate space for such a manipulation the operation of using the ratchet cannot be performed. With the continuing trend to produce more and more compact cars, the open space under the hood of modern cars is becoming increasingly limited, and thus effective tools capable of operating in limited space are very desirable and many times absolutely necessary.
None of the above references discloses, suggests or implies the use of a mechanism comprising the elements of the present invention, as described in detail hereinafter.